In recent, there have been increasing demands to measure blood glucose regularly to diagnose and prevent diabetes. Portable measuring instrument, to be specific, the strip-type biosensor is available for users to measure blood glucose easily and conveniently by simply grabbing the instrument in their hands.
U.S. Pat. No. 5,541,117 discloses preparing a pad with glycosylated haemoglobin assay-specific antibody fixed thereon, transferring the sample onto the fixed pad, and performing computation based on the intensity of reflected light. However, it has shortcomings in that expensive antibody is required, and sensors with consistent quality can hardly be achieved due to the inequalities of porous pad.
U.S. Pat. No. 5,242,842 discloses mixing boronic acid derivatives and glycosylated protein, and measuring blood glucose by spectroscopic method after precipitation or lysis. However, it has difficulties as it requires washing process of boronic acid derivatives, which are lysed with glycosylated protein, and a precise amount of sample should always be maintained to ensure the right results.
Also, U.S. Pat. No. 6,162,645, EP0455225B1 and U.S. Pat. No. 6,174,734 disclose a method of separating protein from sample using solid phase to which immune body is fixed, and determining a relative amount of glycosylated protein using marker compound. However, these conventional electrochemical determining methods of glycosylated protein generally involve collecting glycosylated protein and glycosylated protein-markers competitively on the surface of electrode, and injecting substrate, which stimulates electrochemical reaction with marker, to determine the size of the signal, and is thus has complicated measurement of the concentration of glycosylated protein and can hardly be reproducible.